Answer Happy

Objectives: ● Lab..... Properties of Acids and Bases To understand the pH differences of acids and Bases To learn how to use pH paper To learn about acid-base reactions Introduction: pH Scale: The acidity or the basicity of a solution is typically described by using the pH scale. The relationship between pH and [H₂O*] is described by the following equation. pH = -log[H₂0*] Equation 1 Where, [H3O*] = hydronium ion concentration If pH is below 7, solution is acidic. If pH = 7, solution is neutral. If pH is above 7, solution is basic. When the pH value of a solution is known, it can be used to determine the [H3O*] in the solution by rearranging the equation 1 as shown below. [H_O*] = 10pH Equation 2 pOH Scale: The pOH scale can also be used to describe the basicity or the acidity of a solution. The relationship between pOH and [OH'] is described by the following equation. Equation 3 pOH = -log [OH] Where, [OH] = hydroxide ion concentration FOGHS BA
On the the pOH scale, numbers below 7 indicate a basic solution, where as numbers above 7 indicate an acidic solution. pOH = 7 is neutral. When the pOH value of a solution is known, it can be used to determine the [OH] in the solution by rearranging the equation 3 as shown below. [OH] = 10 POH at 25°C, pH + pOH = 14 Equation 4 Equation 5 pH indicators: pH indicators are chemical substances that can indicate the approximate pH of a solution via color change. eg: pH paper, universal indicator • pH paper: pH paper is used to check if a solution is acidic, basic or neutral. This is done by dipping a strip of pH paper in a solution of interest and observing the color change. The color of the strip is then compared with the color-coded chart that comes with the pH paper kit. The number associated with the color is the pH reading. Form B An
Universal indicator Universal indicator is a liquid substance that has one color in acidic solutions and another in basic solutions. Experiments: Part I - Strong Acids Watch the video and complete the following: Step 1. A small amount of a strong acid solution was poured into a test tube. Step 2. A pH paper strip was dipped into the solution. Notice the color change in the pH paper. Step 3. Compare this color produced to the colors on the pH chart. Record the color on the pH chart that is closest to the color of the pH paper. Record the corresponding pH value. Color of the pH paper Corresponding pH value Strong Acid Step 4. Using the pH value determined in step 3, calculate the [H₂O'] in the strong acid solution. (Write the equation that you would use and show your work.) [H₂O'] in the strong acid solution
Part II Strong Bases Watch the video and complete the following: Step 1. A small amount of a strong base solution was poured into a test tube. Step 2. A pH paper strip was dipped into the solution. Step 3. Compared the color produced to the colors on the pH chart. Record the color change of the pH paper and the corresponding pH value below. Color change of the pH paper Strong Base Step 4. Using the pH value determined in step 3, calculate the pOH value of the strong base solution. (Write the equation that you would use and show your work.) pOH value of the strong base solution= Step 5. Using the pOH value determined in Step 4, calculate the [OH] concentration in the strong base solution. (Write the equation that you would use and show your work.) [OH] in the strong base solution Corresponding pH value Part III - Acid-Base Reactions Watch the video and complete the following: FOCHS B
Step 1. 10 ml of the acid solution (HCI) was poured into a beaker. Followed by 2 drops of universal indicator. Observe and record the color of the solution in the first row of the following table in which the drops of NaOH added is zero. Step 2. A base solution (NaOH) was then added drop-wise to the above beaker. Observe the color change of the solution after adding 10 drops of NaOH, 20 drops of NaOH, 35 drops of NaOH, and 40 drops of NaOH. Record the color of the solution after each addition in the following table. Color of the solution Question 1: Complete the following equation: Drops of NaOH added 10 20 35 40 Focus
Color of the solution Question 1: Complete the following equation: HCI (aq) + NaOH(aq) Question 2: This type of acid-base reactions are called Drops of NaOH added 0 10 20 35 40 reactions. Question 3: Explain why the color of the solution change with the addition of NaOH?